Meter.



Witnesses:

W. H. PRATT.

METER.

APPLICATION FILED MAY 4, 1904.

wmp/gw Patented Apr. 6, 1909.

5 SHEETS-SHEET '1.

l nv erwtcrr;

William N lorlt,

@Mal

, @Ginny W. H. PRATT.

METER.

APPLIOATIUN FILED MAY 4. 1904.

Patented Apr. 6, 1909.

5 SHEETS-SHEET 2f 'pi-g2g ITA/eht, of.

Will iawfatt, f A @Kilt/t@ W. H. PRATT.

METER.

A PPLIOATIN FILED MAY 4, 1904.

Patented Apr. 6', 1909.

' 6 SHEETS-SHEET a.

Inventor by 1 A f ocmpy.

W. H. PRATT.

METER.

APPLIGATION FILED MAY 4, 1904.

Patented Apr. 6, 1909.

5 SHEETS-SHEET 4.

laladflxllv Imi/enter; \)\/il liam H. lOr-att.,

Witnesses @ym/wv* v @f/f4 W. H. PRATT.

METER.

APPLICATION FILED MAY 4, 1904.

Patented Apr. 6, 1909. 5 SHEETS-SHEET 5.

n.- om ta am.

vp MN filthy 40 ways to citent-improvements in the construcuNirEn STATES PATENEIFOWQE# WILLIAM PRATT, OELYNN,

MASSACHUSETTS, AssieNon rro GENERAL arrecato-COMPANY, A coRrjoRA'rroN or NEwYonK. 'Y

METER.

No. 917,13o. i

ATo all whom it may concern):

Be it known that I, WILUIAM H. PRA'rna citizen of the United States, residing at 'Lynn7 county of Essex, State of Massachusetts, have invented certain new anduseful Improvements in Meters, of which the following is a specification.

This invention relates to an 'instrument for measuring the energy or a factor of the energy consumed in an electric circuit orbranch circuit.

More particularly, the invention relates to an integratingwattmeter of the type ernployng an electric motor driving the Wheel train of a dial v register and having its rota A.tion 'retarded by permanent magnets acting on almetallic ydiskSecured to the shaft of the motor. j

The objects ofmy invention are tomake the meter more accurate'forloads Varying between wide limits by increasing both' the torque of the motor; and the damping eHect .of the permanent magnets and at the same time to decrease the weight off the moving4 element of the -meter and thereby decrease friction-in the bearings.

Other objects of the invention are 'to so construct Y'the commutator -or the metermotor thatv the friction between it and theY brushes is reduced to a minimum and to so arrange the brush-holders that the Contact between the brushes and commutator can be delicately adjustedand when once adjusted the brushes and commutator vis' rendered constant throughout the life of the meter;

will remain the same throughout-a long period of use whereby the friction between' also,to provide adequate means for protecting the moving' element of the meter against injury during transportation, and in other` tion of meters of this type f i 1 The novelffeatures of my 'nvention will be definitely indicated in. t e claims appended hereto.

The details of of operation of .the Ameterf *will be better understoodv reference to the following description'taken in connection with the acl companying drawings which'illustrate the 'preferred embodiment of'my. invention.

In the drawings, Figure l isa front fview oi" -the'meter with thecasingremoved; Fig. 2; is a section. onthe line 2-2 of Figui;

3 is a topview'with the casing in seclar'for one o the .field coils;

construction and the Inode Specification of Letters latent.:k 1' PatentediAprll; 1909.

'Application mea may 4, 1904. seriainaaoaere. i i

brush-holders 'broken-away in part; ,Figv 6 is an enlarged sectiothrouvh the commutator on line 6-6 of Fig'. v5 llig. 7 is aper- -spective view of the supporting plate'of onel of the field coils; Fig. 8 is a similar view of the saine having' the radial .fingers bent at right angles to the plate; Fig. 9 is a perspective view of the retaining plate or.col-

41g. l() is a section through one of the eld coils and its supporting plates; Fig. 11 a Asection through the lower bearing; Fig. l2 1s an enlarged view partlyv in section showing the upper portion of the rotating element,

including-a portion of the shaft, the com mutator, and the methodofA connectin the armature leads to the commutator. Fig. 1.5;; Vshows a lower vortion of the'frame` which' sup erts the amp'ing lmagnets.; and Fig. 6A vslows a cross-s ection'on.l theline A B oi Fig. 12 of the lc0mmutator and shaft showving a diierent shape of commutator bar from that shown in Fig. 6.' In the drawings,` l indicates a castingformi'ng the back of the meter and having outwardly extending lugs or projections 2 to whichis secnred the frame' ofthe meter. Mounted in the lower 'partfoi the frame 3 and inthe upper part of an auxiliary upper frame 4 secured to the main tra-ine 3 suitable screws bntf insulated therefrom,4 as shown, are bearings for the vertical shaft- G of the meter which carries the armature 7 andn'ommutator of the motor and the drag disk 9. The armature has-theform of a hollow sphere andco1isist s merely. of the armature coils and ythe?" devices for securing them to the shaft @of then'eter." The spherical form of the'armetureis/'nretferred for the reason that with Vcircular cor sftlie weight o-thearrnature, which forms alarge part of the weight on thestep bearing? of the meter, is considerably reduced; since Vthe rminimum weight `-of wire per amperetnrn incl'osing a 'givenareais required when circular-coils are 'used and. also for-the reason 'that with a sphericalarmaturef circular field Acoils the clearance betweenl these twoparts' "canbe reduced tof a iryinimum tli'us'fnalin'g 'the maximum nuinbfer or the linesof' rorcepf Jthe that it has no i-*interiorsupporting body ject-matter of a'separate application for Letters Patent filed May 24, 1,904 and serially i numbered 209,574. The armature structure position around there consists of a split tubel 10 having a shoulder near each end on which rests a small, stili support or washer 11 of thin, non-magnetic material. This washer and the ends of the split tube 10 are covered with insulating material, such for instance as shellacked paper, as shown at 12. Each coil of armature conductors consists of a plurality of turns of wire wound over the two insulated washers 11 from one to the other, the several coils together forming a sphere having an air core, as shown in Fig. 2, broken away in part. The split tube 10 is provided with suitable clamps 13 by which the armature is secured to shaft 6. The ends of each coil 100 (Fig. 12) extend up along shaft 6, but are insulated therefrom, and through individual openings 101 in a guard 15 ofiber or other insulating material mounted on shaft 6 for a purpose hereinafter to be described. Shaft 6 1s preferably made from a hollow tube for the sake of lightness,l as is shown in Fig. 12 and Fig. 2. Its upper end is reduced in diameter andint this is driven a steel rod 14 of'small diameter insulated outside by a layer of enamel 103 (Fig. 6A) and two layers of silk 104 and japanned, or any other suitable insulation. This rod forms an extenslon to said shaft and carries the commutator 8 and the worm 16 which drives the' dial train 17. Driven on the 'small end of shaft 6 is an insulating sleeve 15 with the upiper er end enlarged for a purpose to be hereina described, through which` are'holes or slots 101 to allow the ends of the armature coils 100 to pass up to the commutator. These are bound tol sleeve 15 by windings of silk or thread 102 and fastened to the commutator bars 18. The segments of the 'commutator l@ consists of sti s of wila'cd in d) 14, bound to the latter at' each yend with silk thread 19. The silk thread 19 and the commutator segments may be then coated with an insulating compound, after which the whole is baked until the' compound is" hard. A portion of the .japan between the segments .may then be scraped out so as to leave air spaces between the several segments to allow for wear.. The

surface'of the cylinder thus formed is then the commutator present a smooth surface, as shown in Figs. 6 and 6A. The 'ends of the armature Coils are then connected to the segments of the commutator in any suitable manner. By` this construction the diameter .of the commutator can be greatly reduced worm 16 in mesh with the worm-wheel 29 mounted on shaft `20 which is journaled in bearings in a frame secured to the upper frame4. On the end of shaft-20 is a finger as is necessary when the worm-wheel is mounted on an extension of the drive shaft of the dial train. The upper end of rod 14 lits in a bore in the upper bearing plug 23 which is clamped in proper position by the clamping bolt 24 between jaws 25 formed integral with the upper frame 4. The end of the bearing plug 23.eXtends above the jaws 25, and adjustably Vmounted thereon is an E-shaped piece 26, each of the lateral arms ot' which has an opening therein, all in axial alinement. The bearing plug 23 eit-` tends through the openings in the two upper arms of' the E-shaped piece and the latter is clamped to the plug by a clamping screw 27, as is shown in Fig. 3.v The shaft of the meter extends through the o ening inthe lowest arm 28 of the E-shap piece 26, and the method of mounting the latter insures coincidence of the center line of the openingin arm 28 and the axis of thev shaft 6.` The interior of the opening in arm 28 is 'beveled off as shown to correspond with the beveled edge of theguard 15. Normally, the E- shaped piece is so mounted. as to leave sutilcient space between the sidesof the opening in arm 28 and the guard 15, to prevent dust.

.from collectinor between the parte and retardl the rotation oipthe sha-ft. The piece 26 may, however, belowered on plug 23 to bring the sides ofthe opening in arm 28 and the guard 15 close together, so that the moving element of the meter may be raised slightly to bring y and from the c ommutator 8 are carried by a block of insulation 33 rigidly mounted on.

theback-of the upper frame4 and at the onthe 'toprof therblo'clz of insul ation 3S. i On two lni-urledfweights 37 by which the Contactr each piece 84 is a binding {screw 35 for inalring electricaliconnection to thev brushes.y Secured'to each-:aria 31v andfvextending out therefrom 1s yetw-threaded rodon which 'are between the brushes andthe cominutator can be adjusted. vThis construction' 'permits a in-uch more delicate adiustnient ofthe con. `tact between 'the brushes 4and commutator than could be secured by the use ot springs,

and furtherinore n possesses the' advantage that when `once adj ustedv the contact will not change throughout the life of the meter,

as the two weights can be readily locked together in theproper position when that position is' once determined.

The ld coils 38 of the'ineter-inotorjare preferably formed from strap or ribbon conductor wound on edge, as it is well known;

` that agirelrnuniber of turns of conductor having a given current-carrying capacity will-occupy less space when ribben conductor is used than'with otherforms of conductor.

Also the ooilsof ribbon conductor wound on i niore'vturns'are usually i-nclosed by the other turns and willbe bronghtto a ninch higher possibleheretcfore with'lield.coilsloound to a considerable thickness with insulating Iedge may be' so; constructed ,thateach turn bears the Vsame relation to the surrounding air as any other, and hence allradiateheat equally, whereas with round wire one or heat tha-'n `the others. For use in the field coils Oneter-nmtfirs, ribbon conductor is particularly advantageous since a coil of ribbon conductor 1s far more rigid than coils v niadefroin ordinary round wire and tor'this .reason the coil can be'inade without an inte-- riorfsulxport.v This `permits mountingv the coil wit its inneredge much closer to the armature ofthe Vmeter-nuotor lthan Vhas been insulation, though other methods 4of insu lating the vseveral,convol'utions of the. coil two coils andthus cut the armature conducone from lanother maybe pursued if desired,

leo

and each field coil is wound in two sections,

bnc within the other and lconcentric there- 1' with. The shape 'ofr the coilsl conforms. to the shape of the armature; in the," meter illustrated, the field' coils'f arecircular. and

the interiordiarneter. of the inner 'section' is but little. greater than the diameter of! the armature thus allowing only'a smallair space between the armature and `field coilsso that practically allof the lines offorce'- cut' the armature conductors. "The two sections of la. -ield coil Vare assembled one within the" other and yareheld between supporting f meterfflprovide the metallic disk- 9. ou

plates'BQ and 40 'of noneinagnetic material,

the art.

ythe coil-;.sections being insulated from the plates and from eachother by `sheet Yfiber 4l f or` other suitable insulating material.

rlhasupporting plate 39'is a punching of non-magnetic sheet nietalihaving a plurality of inwardly-projecting radial lingers e2, as

Vshowninv Fig.' 7, the fingers 42 being long 4and `short alternately and the plate being split at one point to prevent the tlow ofeddy currents therein. The long' fingers 42 are lient at-right angles to the plate, as shown in Fig'. 8,. and inserted between the two coil :fertifms and between the sheets of insulation which separates the coil sections, liber washers 43 being provided between the sides of" eachcoil section and plate 39. The anuularcollar 40 for 'ng the other supporting plate is also a punching of noninagnetic sheet-metal and has holes' therein corresponding` in number .andi position to the long ingerson plate-39 and a gap to prevent the circulation of eddy currents, as shown in Fig'. 9; this'collar is brought up against the'insulating washers 43 on the other side of the coil with the fingers 42 on plate 39, extending through the holes. The

.ends otV the lingers are then bent over to hold 'whole forming al strong rigid structure shown in, section 1n Eig. 10. The supportingv plate 39 extends' out beyond the peripheryof-the cuter coil section at suitable points 'and is provided with openings 44 for the screws' 44 bywhich the two field coils are secured directly to the frame 3 ofthe-meter, one en either side thereof. rlhe two sections .of each coil may be permanently connected .together in series or in parallel, or leads may be brought out from each section of each coil, so that any coinbination'of the seeral coil sections in seriesor Iparallelca'n be inade to obtain the current-carrying capacity and the number ot' turns desired. 3y this construction the interior diameter of the field coils'can be `inade to approximate the diameter of the armature so closely that practically. all oi" the lines of force must cut the armature coils; also'tlie two field coil-s can be mounted so close together that practically all of the lines of force thread the tors in such manneras to exert the greatest lug on trarne?)l and`arranged to be secured 48 adapted tobe cennectedin series with the arniatnreof the nieter-motor to compen- :turning effort, In. this way agreat increase in any posit-ion bythe clamp screw 46 eX-. i tendingthrough a slot therein is an adjustable. arm 47'carrying an auxiliary field coil sate for friction, as is well .understood in` To properlyretard the rotation theshaft 6 and-four permanent magnets Ii9-ar rlnged in pairs, as shown in Figs. 1 and 2, each magnet having its poles reversed relatively to the other vmagnet of that pair, so that two astatic tields'are formed, which the brake-disk 9 intersects. A brass clamp 50 rigidlysupports the ltwo magnets of each .natalie-couple and holds them apart adistance sutlicient to make the vreluctance of the fpath through the diskbetweenthe poles of a magnet very much less than' that of 1 the path across from a pole of one magnet to the opposite pole of the other magnet of that pair. I find by experiment that this arrangement of the magnets ,greatly increases their damping effect. The eddy currents Generated by the two magnets of each pair tIow in opposite directions'in disk 9, the poles ofthe two magnets being oppositely arranged, and the return path followed by thee'd-dy 'currents generated by one magnet isunder the poles of theother magnet of that pair; that is, practically all of the eddy currents generated in the disk by cutting the lines ot force of one of the astatic lields flow in'a single path under the twopairs of poles instead of in two dis! tin'ct paths as they would if the magnets had like poles on the same side of the disk; thus the two magnets act in series and the resistance of the path followed by the eddy currents is reduced to a minimum since its width is not restricted audits length is little more than the length of the magnet poles.v

. smooth to allow for a tree movem'eiit of the damping magnets during the adjustment.

By this construction, the two magnets ofV each pair are always held in the same`posi--- tion relatively each to the other but may be adjusted together toward or away fromthe" center of disk 9 to decrease or increase their damping effect.

The lowerbearing consists of a jewel post' 52 having a spring-supported jewel in its threaded bore'in the lower part of the meter 't'iame 3 and is locked in any adjusted posi- 'tion by a jam nut 55. Fitting' 1n, the' upper end of the' sleeve 54C is --an interiorlythreaded, cylindrical plug 56 vpressed upward by a stitl spring 57 coiled around, the post 52 within sleeve ebutnormally -held vented.

' in the lowest-position, with'thewtiange 6 onits end bearing on the upper end of sleeve 54, by the jewelv post 52, the end of which is threaded and screws into the plug. When.

the meter is to be shipped,V the E-'shaped piece 26 is lowered as above described and ythe jewel post 52 1s unscrewed unt]1 A1t releases the plug 56 'which latter is ressed upward by spring 57, it being guided in its upward movement by sleeve 54. lIn mov-ing hpward', plug 56 engages the lower end of shaft 6 and raises the entire, moving element of the meteruntil the guard 15 comes in contact. with the' sides of the opening in the lower arm 28 of piece 26. Thls upward movement of the shaft however is not great enough to bring the damping disk 9 into' engagement with thepoles of the magnets 49 so that all danger of injury to the disk by coming in contact with the poles of the 'magnets is eliminated. Ii.l desired the E- shape'd piece 26, maybe left permanently in the pos1t-ion to which it is lowered'but I prefer to raise it slightly and lock-it in the raised positionl after the meter is' mounted and ready for service. In this way the movin .element is securely clamped and injury t ereto -during transportation is pre- Secured to the back 1 ofthe meter are connection boards 58 58 to Whichthe circuit wires are brought Vand from which connection is made to the various 'parts Vof the meter- Back of these connection boards is a resistance-59 which is connected in series withv the armature 7 of the mete'nmoto'r and the frictionv compensating coil 48 across the lines; The Efield coils 38 are connected in series in one of the lines or ina suitable'.

shunt, as is well understood by those skilled in the art, and these coils may be 'arranged in series or in parallel as desired.fIn lCase i the meter is used on a three-wire system each coil may be connected in series in one side of thesystem. A suitable casing 61 of sheet-metal incloses the vparts of the'meter and is held thereon by the bolts 52 and winged nuts 63.

I have described my invention as applied to an integrating wattmeter, but Iqdo not wish to be understood' as limited to any particular form of meter, as some features of theI invention are applicable to electrical measuring instruments of all kinds; nor do I wish to.be limited to the recise construc' erein, as many tion which I have shown modlcat'ions'can be made therein andall such modifications I aimto cover in the claims appended hereto;

What I claim as new, and desire to 'secure by Letters Patent 'of the United States, is,-

coils each consistingp, lurality of concentric coil sctions, sid ell'd coils closely,

-' secured to the frame tplates'haying integral projections extending v .l 'f a' plate gon. either. Side.

circular field coils consisting of ribbon conplates veach, of

of, said plates having integral projections Ahold thecoil firmly y,betiveen vthe coil firmly .between them.

. ermee a -sheet-metal plate on either side of the coil,

encircling'the*armature and mountedlclose K v one of said plates being provide together toreduce.thenumber of stray lines of force, substantially'as described.

' 2.1lna meter, `a sphericalxarmature, and

'of plate bet-Ween adjacent coil sections land glfmg 13. in a meter-motor, 'an armature consisting' of a shaft, supports of non-magnetic nurterial thereon, insulation on V said supports and" shaft, and 'coils-ofconductors said fingers extending at an angle tov the en ductor woundon yedge closely encircling said armature. 1f j I 3. llira meter, a spherical armature, and a circular fieldcoilrconsisting of a lurality of concentric coil' 'sections of rib ony conductor wound .on edge' closely encircling said sphere. y

14. ln a metermotor, a shaft, supports of non-magnetic material thereon, insulation on said supports and shaft,and conductors wound over'said supports to form an armature, said conductors extending a greater Lt; En an 'electric meter, a frame, an armature, a'plate secured to the frame and provided-with a .plurality "of integral projections, anda field coil Vofjribbon conductor Wound fon edge held to the plate by said projections. Y lni an electric-apparatus, a frame, an armature, a plate of non-magnetic materia and provided with av plurality ofintegral projections, and' a field coilV composed of,ribbon conductor Wound onedge held to the plate .by said projections.

6.ln a meter-motor, a'fieldfc'oil of ribbon conductor Wound on .edge held between Whichhas a gap therein to prevent the circulation of eddy currents.

7. In ameter, ,an armature, a field coil,

andav pair of supportingl lates therefor, one

riedthereby -bearingon the commutator,

contact pressure commutator.`

thereonl which engage the other plate 'to n them.

8. ln. a-,nieter-motor, a Vhield coil comprising concentric lcoil sections, and a supportingfplateonyeither side thereof,A one, of said said armature the segments of the commutator, ield coils ture, a register driven by theshaft, means for retarding the,v rotation. of the pivotally mountedf brush holder,

between adjacentcoilsections and engagingv brushes the otherplatey v r 9. lin-,an V.lectric measuring instrument, a coil. of ribbon-,conductor Wo nd on edge, and y of said coil insulated therefromygne ofsaidl plates having projectionsiintegralwther'with which engage the other plate. l

gldcln taf-mete .motomlan"armature, a field coil .composedof concentric. coil sectionsfo'f ribbon conductor jvound on edge, a late oneither side of the coil, one of sai 'plates having a plurality of integral projecl i ed rods and arranged to adjusted position.-

tions extendingfhettveerrj adjacent coil vsecy ing on the commutator, other plate Jto hold tions and engaging the idly attached to eac .-brusn-holder, .and a 11. In a meter-motor, an armature, and a field coil composed of concentric coil sections of ribbon conductor Wound on edge and insulated yfrom each other, and a plate on either side o f the coil insulated therefrom, one of said plates having a plurality of integral projections extending between adjacent coi be locked in any 18. A meter shaft, an armature and commutator carried thereby, said armature having its coils connected to the segments of the commutator, field coils mounted coperative relation sections but insulated thereto the armature, a register from and enga irfg the other plate toY hold shaft, means for retarding the rotation of the coil firmly etween them. the shaft,` a block of Ainsulating material se- 12. In a meter-motor, an armature,fa field cured lon the frame, brush-holders pivotally coil composed of concentric coil sections, and mounted Y onv said block,"" brushes carried With a.V plurality` of integral `radial fingersand some 16. A meter'havinga pivoted shaft, van armature andv commutator carried thereby,l

having its coils connected toA mounted 1n cooperative relation to the armaa pivotedcommutator,

Weight adjustable along each of said thread-A 7o the other plate to hold the coil firmly..

Woundoversaid supports to forma hollovvl distance from the shaft than said supports.l d shaft, an

driven by the. shaft, 90

a, brush car-` and an adjustable Weight'for varymgt ebetween said brush and Y a u 95 shaft, a l

carried thereby `bearing onfthe commutator, j

lio.

register driven by. the f;

the-rotation ofV 'Hw'ulltefY carried thereby bearalthreaded-rod rig-v having. a iframe, a pivoted` driven by 'the thereby bearing on the commutator, a rod 'secured to eaoh brush-holder and a weight.

adjustable along each rod and arranged to be locked in 'any adjusted position. l y

' 19. A meter'having a ivoted shaft, an

y armature carried thereby, eld coils mounted in coperative relation to the armature, a

register driven by the shaft, means for retarding the rotation of the shaft, a wrapping of silk thread covering a ortion of the shaft, and a plurality of insu ated com- `mutator segments secured to the shaft about said. covered portion and connected to'the coils of the armature.

- amature carried ther 20. A meter havin a ivoted shaft, an armature carried there y, eld coils mounted in coperative relation to the armature, a-'

A tarding the rotation of the shaft, anda pluralitly of commutator se ents individually insu ated, bound on the s aft by a wrapping of fibrous insulating material about the ends of the segments and connected to the coils of the armature; y

22. A meter having a ivoted shaft, an armature carried thereby, 'leld coils mounted in coperative relation toly the armature, a

register driven by the shaft, means for retarding the rotation of the i haft, and a plu-I rality of individually insul tedcommutator segments bound on the shaft b of silk thread about the ends of the segments an connected to the coilsof the armature.

-2 A meter havin a ivoted shaft, an armature carried there y, eld coils mounted in coperative relation to the'armature, a register driven vby the -shaftmeans for re tarding the rotation of the shaft, fibrous material Wound on the shaft and covering a portion thereof, a coating of an insulating l the armature, a p

a Wrapping v .compound thereon, a plurality of commutator segments insulated and connected to the coils of the armature, and a wrapping of silk thread about the ends of the oomniutatoil segments binding them to the shaft about said insulated portion.

24. In a measuring instrument, a frame, a shaft, a guard thereon, a stationary member mounted on the frame and coperating with said guard, a normally strained helical Spring With its axis substantially in line with the axis of the shaft adapted to move the shaftv when released to bring the guard into engagement with said member, and means for releasing the spring. y

25. In a measuring instrument, a frame, a

vertical shaft, aguard thereon, an adjustable member supported on the vframe coperating 'with said guard and so mounted as to insure alinement `therewith, a normally strained 'spring adapted to move the shaft when re- -leas a threadedl lower bearing post mountedon the frame of the meter, and means -whereby unscrewin said bearing post releases the spring w iich raises the shaft of the meter to bring said guard into engagement with said member.

26. In an electric measuring instrument, a rotatable shaft, anda-device for ret-ardinr its rotation, comprising a metallic' disk mounted on the shaft, a" pair of permanent magnets Whose .lines of force are cut by said dis a clamp for holding the magnets in a definite relation, said magnets having their poles oppositely arranged, means permitting adjustment of said clamp toward and away from the meter shaft, and locking means forV securing the clamp in any adj usted position.

27. In a meter, the combination with its shaft, a damping disk thereon and a damping magnet may rotate, of a removable bearing post for the shaft, and means operated when the post is removed for supporting the shaft with the 'damping disk out of engagement with the `poles of the dampinvmagnet. y In witness whereofa I haye hereunto set m hand this-second day of May, 1904.

' WILLIAM- HfPRATT. Witnesses:

ROBERT SHAND,

DUoALn' MoK. MoKiLLor,

etvveen whose poles the disk V 

